GIANT LAND-TORTOISES 335 



survival in these islands of the reptiles under consideration 

 is entirely due to the absence of such mammals. But, on 

 the other hand, it has to be borne in mind that the giant 

 Siwalik tortoise lived in a land where large mammals — 

 both carnivorous and herbivorous — absolutely sv^armed ; 

 and the same was also the case with the other extinct 

 continental species referred to above. Moreover, we have 

 no evidence of the existence of large tortoises on the 

 continents of the world at an epoch before the advent of 

 large mammals. Still, the absence of the latter from 

 practically all the tortoise-islands is a fact that cannot be 

 disregarded, and must almost certainly have had a very 

 great influence on the development of their chelonian 

 inhabitants. 



In regard to the numbers in which giant tortoises 

 formerly existed on the islands of the Indian Ocean, very 

 kw words must suffice. Writing in 1691, the French 

 traveller Francois Leguat stated that in Rodriguez the 

 tortoises covered the ground so thickly that in places you 

 might walk a hundred paces or more by stepping from the 

 back of one on to that of another. In Mauritius, though 

 apparently less abundant, they were still very numerous 

 down to 1 740 ; and there is ample testimony that during 

 the seventeenth and eighteenth centuries they also swarmed 

 on Reunion, although not a single specimen of the species 

 indigenous to that island has been preserved. The ease 

 with which these reptiles could be captured and carried 

 off, and the facility with which they could be kept alive on 

 board, coupled with the large amount of excellent meat 

 yielded by each, rendered them a valuable food-supply to 

 the crews of ships, and it was far from uncommon for 

 vessels leaving Mauritius to carry off a cargo of four 

 hundred at a time, while in 1759 one of four vessels 



